Southwest, dealing with tragedy, posts quarterly earnings.

DALLAS (AP) — Lower income taxes are helping Southwest Airlines overcome cheaper tickets and higher costs for fuel and labor.

Southwest reported a 22 percent jump in first-quarter profits Thursday, in line with Wall Street expectations.

The carrier's financial performance is still being overshadowed by a tragedy last week in which a passenger was killed — the first accident-related death of a passenger in the airline's 47-year history.

"It remains a somber time" at the airline, said CEO Gary Kelly. He extended condolences again to the family of the woman who died when a piece of an exploding engine from the plane pierced the cabin. Kelly pledged to cooperate with investigators and vowed that Southwest never compromise on safety.

The airline also revealed plans to fly to four cities in Hawaii, not just Honolulu. That decision raises the stakes in a looming competition with Hawaiian Airlines and other carriers that fly to the islands. The Southwest flights are expected to start late this year or early in 2019.

Southwest also said it will lease more coveted takeoff and landing slots at LaGuardia Airport in New York and Washington Reagan National Airport just outside the nation's capital from Alaska Airlines, allowing it to expand at two airports that are essentially full.

Southwest's first-quarter profit of $463 million was padded by a 28 percent decrease in income taxes compared with a year ago, a savings of $54 million.

Excluding items such as fuel-hedging contracts, the Dallas airline said it would have earned 75 cents per share, matching the forecast of analysts surveyed by Zacks Investment Research.

Revenue rose 2 percent to $4.94 billion. That's record for the first quarter, but still shy of the $5.02 billion that analysts in the Zacks survey expected. Shares slid 4 percent before the opening bell.

Southwest boosted revenue despite a drop of nearly 5 percent in the average one-way fare, to $146.33 — reflecting slightly short trips and competition on key routes. However, the airline carried 6 percent more passengers, and the average flight was more full — 81.5 percent of seats were sold, compared with 79.9 percent a year earlier.

Labor costs roses 5 percent and fuel costs grew 6 percent. But Southwest said second-quarter cost increases would be modest, even with possible pay raises for mechanics and what it termed a preliminary estimate of expenses related to the fatal accident — Southwest did not give a figure for those.